Identification of a locus on Agropyron cristatum chromosome 6P that interacts with wheat genes to produce yellow-green leaves.

BACKGROUND

Wide hybridization is crucial for broadening the genetic basis of common wheat. Agropyron cristatum (2n = 4x = 28, PPPP), a wild relative of wheat, harbors numerous favorable genes for genetic improvement. The variability related to the expression of alien genes in different wheat backgrounds is a crucial factor that limits the effective utilization of these genes.

RESULTS

In this study, the introduction of chromosome 6P from A. cristatum into different wheat backgrounds resulted in different leaf colors: green in plants with the Fukuho background and yellow‒green in plants with the Jimai 22 background. Genetic analysis suggested that yellow‒green leaves were caused by gene interactions between chromosome 6P and genes from the Jimai 22 background, which negatively affected agronomic traits. To determine the locus on chromosome 6P responsible for yellow‒green leaves, six wheat-A. cristatum deletion lines and five wheat-A. cristatum translocation lines were crossed with Jimai 22 to produce F progeny for leaf color investigation. We found that the F progeny carrying the short arm of chromosome 6P (6PS) presented yellow-green leaves, and the relevant locus was ultimately mapped to 6PS (0.81-1.00). A total of 50 A. cristatum genes related to chlorophyll catabolite reductase and chloroplast development were annotated within this interval.

CONCLUSIONS

A locus on chromosome 6P of A. cristatum that caused a yellow-green leaf in the Jimai 22 background was mapped to chromosome 6PS (0.81-1.00). This study provides valuable germplasm for the study of leaf color and guidance for the use of valuable genes on A. cristatum chromosome 6P.